docs: def unit_response(self):
          """Calculate :ref:`pysynphot-formula-uresp`.
  
          .. warning::
  
              Result is correct only if ``self.waveunits`` is in Angstrom.
  
          Returns
          -------
          ans : float
              Bandpass unit response.
  
          """
          hc = units.HC
  
          if hasattr(self, 'primary_area'):
              area = self.primary_area
          else:
              area = refs.PRIMARY_AREA
  
          wave = self.GetWaveSet()
          thru = self(wave)
  
          return hc / (area * self.trapezoidIntegration(wave, thru*wave))